Biomarkers Could Lead to Earlier Diagnosis

A new research paper sheds light on the way antibodies distinguish between different but closely related 'biomarkers' - proteins which reveal information about the condition of the human body. This new understanding could enable pharmaceutical companies to develop new technologies for quickly diagnosing and treating fatal diseases.

All diseases have proteins, or concentrations of proteins, specifically linked to them called biomarkers. Identifying these can prove a powerful diagnostic tool. These biomarkers are detected by immunoassays – a test which mixes a substance (for example blood, urine) with antibodies, which bind to the protein if it is present. The antibodies can then be measured to identify the level of the biomarker, which in turn indicates the presence and extent of an illness.

Antibodies bind with high specificity to one protein molecule or a limited group of molecules (for example hormones), which is why we can use antibodies to test for specific biomarkers. Problems arise when they bind to groups of similar hormones that are associated with normal bodily changes. This leads to false positives and therefore unreliable information. The research shows how different proteins are made up, and therefore how they can be identified reliably.

The highly sought solution is 'intelligent selection' of antibody-specific interaction sites on hormones that can differ from similar sites of other hormones by just one molecule.

Understanding these structural differences explains the observed selectivity in the full hormones. Armed with this knowledge, scientists can develop intelligent epitope selection to achieve the required assay performance. This means reliable tests can be developed to indentify the presence of different hormones – in this case the presence of hCGβ which indicates cancer, as opposed to LH, which is always present.